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Indirect water tank temperature issues

Hello all. I replaced my boiler/water heater about 2 years ago with Lochinvar KBN 110 and Bradford white PowerStor SW-2-65-L idirect water tank
I also had the plumber install Honeywell AM-1 mixing valve on the tank.
For the most part everything works great but sometimes my hot water is luke warm. Doesn't happen often and i noticed mainly it happens when there is a large water usage
Most recent it happened was yesterday. Went to sleep and water was warm at full hot open and after I woke up, its fine. Another few times it happened
when wife wanted to use the soaking tub. my WAF tanked those 3 times :)

I have my mixing valve set at 120 and water temp in the tank is 140. I have my lochinvar set to 4 degree so it kicks on when its 135.
Temp sensor on the indirect is located towards the bottom of the tank. Temp sensor seems to work fine.
I did notice that mixing valve siezed on me. I tried to adjust it and its not turning. Any ideas on whats happening and how to fix it?
I'm guessing mixing valve got something inside it stuck and its not mixing water correctly?
not sure what else to check. I called the plumber and he told me to just get another mixing valve and replace it. but I want to make sure i do it right and
don't have to do this again.

Any recommenadation on a mixing valve to get?

here is an album to the pictures:

https://photos.app.goo.gl/B4YjLktjwofjd4dR9

Comments

  • kcopp
    kcopp Member Posts: 4,418
    The mix valve sometimes needs to get "woken up". That involves turning the knob up and down a few times. I would be willing to bet that the knob has been locked in place w/ the set screw. Loosen it up and pull up. It should turn freely.
  • kalex1114
    kalex1114 Member Posts: 104
    kcopp said:

    The mix valve sometimes needs to get "woken up". That involves turning the knob up and down a few times. I would be willing to bet that the knob has been locked in place w/ the set screw. Loosen it up and pull up. It should turn freely.

    i did remove the set screw. no movement on the knob. its stuck
  • kalex1114
    kalex1114 Member Posts: 104
    Yep just confirmed it. took the screw out. pulled the knob out a bit to engage it and tried to turn the knob. no movement at all
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,272
    Hi, Can you post a photo of the valve? It might be possible to remove the top of the valve and then get to and descale the innards.

    Yours, Larry
  • kcopp
    kcopp Member Posts: 4,418
    In that case...from the pictures you sent a link to I would just swap it out for another Honeywell. Unfortunately that is the only valve that will fit in there w/o doing some re-piping. You could try to disassemble and clean as Larry suggests if you have the time and want to give it a go...
  • JohnNY
    JohnNY Member Posts: 3,226
    That mixing valve maxes out at 120°. I find that mixing valves don't work well at either extreme end of their settings except at prolonged draw. You've also got no heat trap installed.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
  • kalex1114
    kalex1114 Member Posts: 104
    JohnNY said:

    That mixing valve maxes out at 120°. I find that mixing valves don't work well at either extreme end of their settings except at prolonged draw. You've also got no heat trap installed.

    which mixing valve would you recommend?
  • kalex1114
    kalex1114 Member Posts: 104

    Hi, Can you post a photo of the valve? It might be possible to remove the top of the valve and then get to and descale the innards.



    Yours, Larry

    Here is the picture:


  • HVACNUT
    HVACNUT Member Posts: 5,804
    edited October 2019
    How many gallons is the soaker tub? If the mixing valve is operating properly, I would raise the tank temp to 160°.
    If the mixing valve is faulty, then swap out with the same. It's a good valve.
    If it were mine, I'd keep the tank at 160° regardless.
    The tape thermometer is NG, and the bulb one is probably too not accurate where it is. Get a good 3/4" surface mount clamp thermometer.
  • hot_rod
    hot_rod Member Posts: 22,021
    In hard water conditions, which it looks like you have based on the valve to the right, you may need to descale them yearly or maybe even every 6 months

    Consider a spare so you can rotate in a cleaned one when it seizes.

    Probably the highest maintenance valve out there, thermostatic mixers.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • kalex1114
    kalex1114 Member Posts: 104
    edited October 2019
    > @hot_rod said:
    > In hard water conditions, which it looks like you have based on the valve to the right, you may need to descale them yearly or maybe even every 6 months
    >
    > Consider a spare so you can rotate in a cleaned one when it seizes.
    >
    > Probably the highest maintenance valve out there, thermostatic mixers.

    I have a whole house water softener installed not sure why water is hard. Shouldn’t be

    @hvacnut - I can keep the tank at 160? It won’t damage the tank being so hot?

    How hard is it to rotate them?
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,272
    Hi, Sorry I missed the link to your images... was on my phone. I think my question has been answered, in that the guts of the valve are clearly accessible and likely easily replaced. Keeping a spare on hand sounds like it will eliminate most of the downtime when the valve misbehaves.

    Yours, Larry
  • JohnNY
    JohnNY Member Posts: 3,226
    kalex1114 said:

    JohnNY said:

    That mixing valve maxes out at 120°. I find that mixing valves don't work well at either extreme end of their settings except at prolonged draw. You've also got no heat trap installed.

    which mixing valve would you recommend?
    https://www.supplyhouse.com/Honeywell-Sparco-AM101-USTG-1LF-3-4-Lead-Free-Union-Sweat-Mixing-Valve-w-Temperature-Gauge-70-145F
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
    kcopp
  • kalex1114
    kalex1114 Member Posts: 104
    > @JohnNY said:
    > (Quote)
    > https://www.supplyhouse.com/Honeywell-Sparco-AM101-USTG-1LF-3-4-Lead-Free-Union-Sweat-Mixing-Valve-w-Temperature-Gauge-70-145F

    Thank you. Is this same model? Honeywell AM101-US-1 Sparco Thermostatic Mixing Valve, 3/4" Union-Sweat 100-145F https://www.amazon.com/dp/B002DGEOJC/ref=cm_sw_r_cp_api_i_STfRDb06RJCXN
  • JohnNY
    JohnNY Member Posts: 3,226
    Looks like it. Yes.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
  • kalex1114
    kalex1114 Member Posts: 104
    JohnNY said:

    Looks like it. Yes.

    Thank you.
    do I need to drain the indirect to swap it? or just close of supply valves and open a faucet to relieve pressure and swap it?
  • Intplm.
    Intplm. Member Posts: 1,880
    @kalex1114 Or maybe change to something like this
  • kalex1114
    kalex1114 Member Posts: 104
    Intplm. said:

    @kalex1114 Or maybe change to something like this

    may ask why change?